Applicant has invented novel methods for bypassing obstructions in arteries and for performing other transvascular medical procedures, wherein a catheter device is inserted transluminally into the blood vessel or other luminal anatomical structure and a tissue-penetrating element (e.g., a puncturing member or a flow of energy) is passed out of the catheter, through the wall of the blood vessel or other anatomical structure in which the catheter is positioned, and into a second blood vessel or other target anatomical structure. In this manner one or more interstitial passageways is/are formed from the blood vessel or other luminal structure in which the catheter is positioned, to a second blood vessel or other target tissue. These transvascular procedures, and certain passageway forming catheters which are useable to perform these procedures, have previously been described in U.S. patent applications Ser. No. 08/730,327 entitled METHODS AND APPARATUS FOR BYPASSING ARTERIAL OBSTRUCTIONS AND/OR PERFORMING OTHER TRANSVASCULAR PROCEDURES, filed on Oct. 11,1996 and U.S. Ser. No. 08/730,496 entitled, A DEVICE, SYSTEM AND METHOD FOR INTERSTITIAL TRANSVASCULAR INTERVENTION, filed Oct. 11, 1996.
In performing the above-summarized transvascular procedures, it is important that the passageway-forming catheter be properly positioned and oriented within the body in the order to ensure that the tissue-penetrating element will form the desired interstitial passageway, at the desired location. If the catheter is improperly positioned or improperly oriented, the resultant passageway(s) may fail to perform their intended function (e.g., to channel blood from one location to another) or the tissue penetrating element of the catheter may perforate or traumatize tissue(s) other than those intended to be canalized.
In many of the passageway-forming catheters devised by applicant, it is necessary to precisely control the rotational orientation of the catheter in order to accomplish the desired aiming of the tissue-penetrating element. However, when the passageway-forming catheter is formed of relatively small diameter, thin-walled polymeric material capable of navigating small, tortuous blood vessels, the catheter shaft may lack sufficient structural integrity to efficiently transfer torque from the proximal end of the catheter to the distal end thereof. Such diminished torque transfer of the catheter shaft can prevent or interfere with the precise rotational orientation and positioning of the distal portion of the catheter prior to formation of the extravascular passageway.
Additionally, to facilitate the use of any on-board imaging system (e.g., an intravascular ultrasound system inserted or built into the passageway-forming catheter) or any separate intracorporeal or extracorporeal imaging services intended to assist in the precise aiming of the tissue-penetrating element, it is desirable for the tissue-penetrating catheter to be provided with appropriate markers or other indicia to enable the operator to utilize to discern the present rotational orientation and position of the catheter and the projected path of the tissue-penetrating element.
Thus, there remains a need in the art for further development and modification of applicant's previously described passageway-forming catheter devices so as to provide for i) improved torque transfer to the distal portion of the catheter and ii) precise rotational orientation and aiming of the catheter prior to deployment of the tissue penetrating element.